The purpose of the conference is to provide a forum for the interaction between scientists representing varying disciplines, who are interested in the mechanisms by which extracellular signals are transduced at the cell surface membrane level. The conference is held in an environment that promotes free exchange of data and ideas. The number of speakers is being held to five per day so that in depth presentations, as well are extensive discussions, are possible. Ample time is provided for non-formated exchange between the conferees. The topics to be covered in the 1985 conference are: Dual Signal Transduction in Adenylate Cyclase, Structure and Function of Receptors that Couple to Adenylate Cyclase, Phosphatidylinositol Metabolites and Signal Transduction, Oncogene Products as GTP Binding Proteins, Ca2+ Channels and Their Regulation, Cyclic Nucleotides in Neurobiology, Self-Transducing Receptors and Signal Transduction in Response to Light. These sessions thus will cover not only established signal transducing systems but also new systems that are as yet being described. Particularly noteworthy are the sessions on oncogene products that have in the past year been described as GTPases, the session on hormonal regulation of Ca2+ channels and the session on PI turnover, since they represent areas where new and novel mechanisms for conversion of the extracellular signal are being found.